Aik-heating furnace



R. T. CRANE.

Hot Air Furnace.

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Patented March 20, 1860. w

UNITED STATES PATENT CFFTCE.

RICHARD T. CRANE, OF CHICAGO, ILLINOIS.

AIR-HEATING FURNACE.

Specification of Letters Patent No. 27,530, dated March 20, 1860.

To all whom it may concern:

Be it known that 'I, RICHARD T. CRANE, of Chicago, in the county of Cook and State of Illinois, have invented a new and Improved Air-HeatingFurnace; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the annexed drawings, making a part of this specification, in which Figure 1, is a longitudinal vertical section of my invention taken in the line 00, m, Fig. 3. Fig. 2, is a transverse vertical section of the Fig. 3, is a horizontal section of the same, taken in the line 2, 2, Fig. 1.

Similar letters of reference indicate corresponding parts in the several figures.

This invention relates to an improved airheating furnace in which steam is employed as a heating medium.

To enable those skilled in the art to fully understand and construct my invention I will proceed to describe it.

A, represents a chamber which may be of rectangular form, the walls being of masonry and having an induction opening a, in its lower part and an eduction opening I), in its upper part. This chamber A, is the airheating chamber and within it the fire-chamber, boiler, and steam pipes and steam chamber are placed.

B, is the fire-chamber and C, the boiler which encompasses the fire-chamber at its top rear and sides, the fines o c, passing longitudinally through the boiler, one set of fines 0, being return flues and communicating with the lower end of the smoke stack D. The flues 0, c, are connected at the back part of the boiler by a chamber (Z. The fire-chamber is placed directly over an ash-pit E, and the boiler C, may extend the whole length of the chamber A, but is not equal to it in width. The fire-chamber, boiler and flues may be of cast metal and they are fitted at the lower part of chamber A, as shown plain in Figs. 1 and 2.

F, represents a series of vertical tubes which are attached to and communicate with the boiler C. These tubes communicate at the upper ends with a chamber G, which extends the whole length of the chamber A, but like the boiler C, is not equal to it in width, see Fig. 2. The chamber G, may be of cast and the tubes F, of wrought metal. The tubes F, are placed in parallel rows and the tubes of one row are placed in line with the spaces between the tubes of the adjoining rows, as shown clearly in Fig. 3. The tubes F, are sufliciently high to place the steam chamber G, quite near the top of the airheating chamber A, the top of the latter being formed of a metal plate 6.

From the chamber G, two horizontal pipes H, I, pass out through the chamber A, one at each side. The pipe H, communicates with a metal bowl or vessel J, which is attached to the side of the chamber A. The bowl or vessel J, has an india-rubber top f, secured to it by a cap 9, and on this india-rubber top an upright it, rests, said upright being attached at its upper end to a lever 2', which has its fulcrum at j, a weight is, at one end and a cord or chain Z, attached to the opposite end, s'aid cord or chain having a valve m, attached to its lower end which valve fits in the upper end of a pipe K, that leads into the ash-pit E, below the fire-chamber.

The pipe I, communicates with a bowl or vessel L, similar to J. The bowl or vessel L, is also provided with an india-rubber top a, which is secured on the bowl by a cap 0.

M, is a pipe the lower end of which passes into the ashpit E, and the upper end passes into the bowl L, and extends up nearly to the india-rubber top a. In the upper end of pipe M, a trilateral plug 70, is fitted said plug being attached to a disk 9, which has a stem 1", that passes up through the rubber 12, and has a cap or weight 8, screwed on its upper end.

The operation is as follows :The boiler C, is supplied with a requisite quantity of water, (shown in blue tint Figs. 1 and 2,) and a fire is kindled in the fire chamber B. Steam will soon be generated in the boiler C, in consequence of a great heating surface being presented to the fire-chamber. The steam fills the tubes F, and chamber G, and a large radiating surface is thereby obtained in the chamber A, the air in passing up through said chamber A, being quickly heated to the temperature of the tubes and chamber G. By this arrangement or disposition of the tubes F, boiler C, and chamber G, the air in passing through A, is brought directly in contact with the heating parts and passed between the tubes F, so that a large volume of cool air is quickly heated. The heated air may be conveyed from A, through any proper tubes to the desired compartments and when the pressure of steam in the tubes F, and chamber G, exceeds a certain point the pressure will raise the elastic top f, of the bowl J, the gravity of weight 70, being overcome, and the valvem, will be depressed and the supply of oxygen to the fire diminished. By this means the device is rendered self-regulating. In case the pressure of steam in the tubes F and chamber G, should become very great in consequence of a very quick fire the steam will raise the elastic top n, of the bowl L, and the disk 9, will be elevated free from the top of the tube M, the plug 39, serving as a guide, and the Weight 8, being overcome, the steam will rush down the pipe M, into the ash-box E, and extinguish the fire. The fire-chamber and ash-pit are provided with necessary doors and a door, 6* may be placed at the base of the smoke stack for the purpose of facilitating the cleaning of the fines and stack. Thus it will be seen that the device is rendered perfectly safe and also selfregulating and a large volume of air may be heated with the smallest possible consumption of fuel.

I do not claim separately the employment or use of vertical steam tubes as heat radiators, nor do I claim any of the parts when viewed separately and irrespective of the end to be attained; but, having thus described my invention,

WVhat I do claim as new and desire to secure by Letters Patent, is

1. The combination with an air chamber A, and fire chamber B, of the boiler C, tubes 

